The US military may be guilty of war crimes for killing large numbers of civilians in a sharply stepped-up campaign of air strikes in Somalia over the past two years, Amnesty International has said.

The organisation says it had been able to document 14 civilians killed in investigations of just five air strikes, a tiny fraction of at least 110 such strikes that the US military says it has launched since June 2017.

The US military rejected Amnesty's report. It says it has killed 800 militants in air strikes in Somalia over that period, but has not wounded or killed a single civilian.